Change-over key or switch for telephone exchanges and the like



March 20, 1934. M. B, RICHTER CHANGE-OVER KEY OR SWITCH FOR TELEPHONE EXCHANGES AND THE LIKE Filed Feb. 7, 1933 3 Sheets-Sheet 1 March 20, 1934. M, B R T R 1,951,530

CHANGE-OVER KEY OR SWITCH FOR TELEPHONE EXCHANGES AND THE LIKE Filed Feb. 7, 1955 s Sheets-Sheet 2 F793 I F794.

March 20, 1934. M. B. RICHTER CHANGE-OVER KEY OR SWITCH FOR TELEPHONE EXCHANGES AND THE LIKE Filed Feb. '7, 1933 3 Sheets-Sheet 3 Patented Mar. 20, 1934 F F l C CHANGE OVER KEY R SWITCH FOR TELEPHONE EXCHANGES AND THE LIKE Morten Balthazar Richter, Copenhagen, Denmark Application February '7,

1933, Serial No. 655,563

In Denmark March 10, 1932 9 Claims.

The invention relates to a change-over key adapted for telephone exchanges and the like, which key amongst other things may be used as operators key (for instance combined listening and ringing key) in change-over and central boards of telephone exchanges or which may generally be used as switch in many other cases where a number of electric circuits are to be closed or interrupted through a single manipulation.

In such change-over keys the shifting member serving to operate the contact springs and coacting directly or indirectly with the same, usually like a lever, is mounted to swing on a fixed pivot and is capable of occupying in addition to a mid position one or the other of two extreme positions corresponding to three different ways in which the contact springs may be conductively connected with or separated from each other. Such an arrangement has the disadvantage that the shifting member, when suddenly released in one extreme position then under the influence of springs and due to inertia may tilt in an unintended manner past the mid-position to the other extreme position, thereby effecting a false contact operation.

This disadvantage is obviated by the changeover key constructed according to the invention which is mainly characterized by the fact that the shifting member is mounted to rock around one or the other of two spaced parallel axes of rotation. Thus it may be swimg around one of these axes when it is to be moved from the midposition to one extreme position, and around the other of these axes when it is to be moved from the mid-position to the other extreme position. In such a change-over key the tendency to effect false shifting under the above named circumstances will practically be eliminated. According to a further feature of the invention the shifting member is maintained yieldingly in its normal position (the mid-position) by one or more separate springs. Thus since the contact springs do not-as otherwise usualserve in the present case by their elasticity both, to maintain a suitable pressure of contact against each other and to keep the shifting member in the midposition, these contact springs may, without any harm arising, be made somewhat smaller whereby the device becomes more compact.

It is to be emphasized that the invention is not restricted to any special mounting, shape or combination of contact springs, as these factors may be varied in many different ways.

The shifting member may be mounted on two fixed pivot studs or the like which extend through slots or notches in said member, or the inverted arrangement may be used in which case there are secured upon the shifting member two pivot studs or the like which may move in slots or notches in fixed supporting parts.

Other features of the invention will appear from the following description with reference to the accompanying drawings, in which two constructions of the invention of the last named kind are shown.

Figures 1, 2 and 3 show front view, side elevaticn andrear view respectively of a change-over key constructed according to the invention, the shifting member, acting directly upon the contact springs, in all three cases being illustrated in its mid-position.

Figure 1a is a perspective view of a cover or cap member adapted to protect and embrace the uppermost part of the frame of the change-over key shown in Figures l-3,

Figures 4 and 5 show a front view of the uppermost portion of the same key, the shifting 1iiember being shown in one and the other extreme position respectively.

Figures 6 and 7 show front View and side elevation respectively of a second construction of the change-over key, in which the shifting member acts indirectly upon the contact springs and Figures 8, 9 and 10 show details of the same, viz. a front view of a sliding member with appertaining locking plate, a side elevation of the same sliding member and a front view of the other sliding member with the shifting member in an extreme position, respectively.

The contact springs and movable parts of the change-over key illustrated in Figures 1 to 5 are mounted in a frame comprising a plate a which in its uppermost part is bent into U-shape, see particularly Figure 2, thereby forming a horizontal part a upon which the cover I) shown in Figure la is to be secured, and a vertical front part a In its lowermost portion the plate a is provided at its sides with two inturned parts a In the rectangular space surrounded by the parts a, a :1 which space at its front side is closed by a plate 0, the contact springs 12 are clamped between insulating members which feature, however, forms no part of the present invention.

In this construction the shifting member con sists of a substantially semicylindrical metal block 6, an L-shaped roller carrier 6 of metal and an insulating handle 7, which three parts are connected together by a screw e In the two vertical flaps of the carrier e two pivot studs :1

are secured upon each of which two insulating rotatable rollers g, g are mounted that are adapted to operate the contact springs d. The ends of the pivot studs 7' are mounted and may be rotated and displaced partly in closed curved slots is in the rear plate a and partly in downwardly open slots or notches Z in the plate member a see particularly Figures 3 and l. The shifting member or rocking lever f, e, e is normally held in the mid-position shown in Figures 1 to 3, where the studs 9' lie in the uppermost ends of the slots is and Z, by means of a substantially s-shaped wire spring m which urges the shifting member as a whole upwardly. The uppermost end of this spring is seated in the lower rearmost part of the carrier e while the lowermost end of the spring is seated in a hole in a rigid plate piece n. The ends of the spring are able to rock in their supports. At the back surface and the front surface of the carrier 6 a thin insulating layer 0 and 0 respectively is secured.

When the shifting member is swung to the left extreme position it rocks on the right pivot stud a", and the left pair of rollers g, 9, Figure l, t ien penetrates like a wedge between the extended bent ends it of two of the contact springs d and thereby effect the desired contact combination. If the handle on the other hand is swung to the right extreme position, Figure 5, the shifting member rocks around its left axis of rotation, and the right pair of rollers g, Q then in a similar manner acts upon two different contact springs and effects another contact combination.

Moreover it will be understood that the dinerent ways in which the closing and the interrupting of contacts can be produced may be widely varied by suitably choosing the number of contact springs and the arrangements of the latter and th shifting member, the salient feature of the invention residing in the fact that the shifting member may be turned at will around one or the other of two spaced parallel axes of rotation.

In the embodiment shown in Figures 1 to 5 the spring m is so formed and arranged that the shifting member is automatically returned to the mid-position when the handle 1 is released in the right extreme position of the shifting member, Figure 5, because in that position the central axis of the upward thrust is located to the right of the left hand pivot stud 7', whereas the shifting member will remain in its left extreme posit-ion, Fig ure 4, upon release of the handle, since in that case the line of the direction in which the spring exerts a pressure upon the carrier e will lie at the right side of the right pivot stud 7', so that the shifting member must be moved back by hand to the mid-position.

According to the invention means are preferably provided for preventing the shifting member from being moved downwards as a whole if a vertical pressure is exerted upon the handle f. For this purpose the spring system (here consisting of the spring m) acting upon the shifting member might be made particularly strong, but as a rule it is preferred in order to attain the effect just indicated to interpose a suitably formed cam guide or cam groove guide or the like between the shifting member and the fixed frame, which guide is so arranged as to allow the shifting member to swing around either of the two axes of rotation, but prevents any essential vertical displacement of the same as a whole.

In the construction shown in Figures 1 to 5 such a cam guide is provided in the following Way. The length of a horizontal edge 19 at the lowermost part of the carrier e is approximately equal to the mutual distance of two pins q rigidly secured in the frame a, see particularly Figure 3, and above this edge p the lateral edges 10 p of the carrier are cam-shaped, the horizontal width of the carrier increasing upwardly. Thus any appreciable downward movement of the shifting member as a whole is prevented by the pins q, whereas the shifting member is free to rock on either of the studs 7', the cam edge p in question thereby passing the corresponding pin q closely or sliding thereon.

It would generally not be advisable to prevent vertical displacement of the shifting member by m ans of the curved slots is and Z since in such case the studs 7' might easily be clamped by wedge action in these slots. In the embodiment shown in Figures 1 to 5 the studs may fit comparatively loosely in the slots, and thus no friction arises at these points by the manipulation of the key.

The substantially U-shaped cover I), Figure 1a, which has been omitted in Figures 1-5 in order to avoid crowding of the drawings, is adapted to snugly fit the uppermost portion of the frame (L and to cover the curved slots is and Z and both ends of the pivot studs 7', even in the extreme positions of the shifting member, and for this purpose the front plate of the cover is provided with two semicircular tongues b In the arrangement illustrated in Figures 1 to 5 he direction of movement of the rollers g acting upon the contact springs is mainly parallel with the longitudinal direction of the contact springs, see particularly Figure 1, and each roller directly acts on one contact spring which is also jij which here comprises a metal lever 6 having an insulating handle f and two cam pieces g and g arranged side by side in somewhat angularly staggered positions, see particularly Figure 10. In the normal position of the key the lever e occupies the vertical position shown in Figures 6 and 7 from which it may be swung in either direction around one or the other of the two pivot studs 9' respectively, which are guided in curved slots k all in a manner similar to that described above with reference to the first construction.

The shifting of the contact springs is effected by vertically displaceable L-shaped sliding members r and 9' which are guided on fixed studs 3 and provided each with a roller t and 2 respectively for co-operation with the cam piece 9 and g amongst other things serve to maintain the slidl-L.-;

members in position in the key. Between sliding member and the locking plate associated therewith there is stretched a helical spring 51: and m respectively, and when the sliding members have been placed upon the guiding soc studs 8, and the locking plates have been mounted in position on the sliding members the said springs tend to move the sliding members upwards and to move the locking plates downwards. As a descending movement of the latter is prevented by the studs 3 both of the rollers 15 and r are pressed yieldingly upwards against the ends of the respective cam pieces 9' and g whereby the shifting member is held in its mid-position. In the construction shown one cam piece 5/ is so shaped that the lever 6 will remain stationary in the corresponding extreme position when released, whereas the lever is automatically returned by spring action from the other extreme position (that shown in Figure 10), if the handle is released in that position.

On the sliding members r and r insulating strips are rigidly secured which strips have teeth u and a respectively which engage, upon consecutive depression of sliding members, lateral fins o and s respectively of the contact springs to operate the latter.

A screw y threaded into the uppermost portion of the frame a of the key engages a curved slot 2, Figure 19, in the lever e and thereby prevents displacement of the latter as a whole, which effect corresponds to that afforded by the camguide of the construction shown in Figures 1 to 5.

In addition to the above named modifications oi the constructions shown in the drawings, many other changes of the same may be effected without departing from this invention. Thus, the lever may be provided with more than two cam pieces, for instance with two cam pieces at each side, one behind the other, so that the number of contact springs may be doubled. Furthermore one or more springs of a kind differing from the springs shown may be used for normally keeping the shifting member in mid-position.

Having thus fully described my invention I claim as new and desire to secure by Letters Patent:

1. A change-over key for telephone exchanges including a set of contact springs, two spaced parallel pivotal elements and a shifting member supported on said elements to rock on either of said elements, for shifting said springs into different contact positions, and an operating handle for rocking said shifting member.

2. A change-over key for telephone exchanges including a set of contact springs, two spaced parallel pivotal elements and a shifting member supported on said elements to rock on either of said elements, for shifting said springs into difierent contact positions, and yielding means, independent of said contact springs for maintaining said shifting member normally in a definite intermediate position on both of said pivots, and an operating handle for rocking said shifting member.

3. An operators key for telephone exchanges, composing in combination a plurality of sets of contact springs, a manually operable shifting block for controlling the positions of said springs, two spaced parallel pivotal elements for supporting said block to permit it to assume three positions, viz. a neutral mid-position on both pivots and two extreme end positions, when tilted on one or the other of said pivots and means on said block for operating in said end positions different sets of contact springs.

4:. An operators key for telephone exchanges, composing in combination a plurality of sets of contact springs, a manually operable shifting block for controlling the positions of said springs,

two spaced parallel pivotal elements for supporting said block to porn it it to assume three positions, via. a neutral mid-position on both pivots two extreme end positions, when tilted on one or the other of said pivots, means on said block for operatin in' said end positions different sets or" contact springs, and a positioning spring for said shifting block, independent of said contact springs, for normally maintaining the block in the neutral position on both pivotal elements.

5. An operators key for telephone exchanges or he like, comprising a frame having two oppoitely disposed walls wo pairs of oppositely isposed slots in said walls, each pair being widely paced from other pair, a shifting block disosed between said walls and having two spaced para-lilo pivot studs, each stud engaging one pair site wall slots, so that said block is permitted to rock on either of two spaced pivotal supports, two sets of contact springs mounted on said frame, means on said block for operating one or the other set said contact springs when the block is rocked in one or the other direction, and an operators handle on said block for rocking it on either pivotal support.

6. An operators key for telephone exchanges or the like, comprising a frame having two oppositeiy disposed walls and two pairs of oppositely disposed slots in said walls, each pair being widely from the other pair, a shifting block dis- .ot each stud engaging one pair u-e wall slots, so that said block is permitted to rock on either of two spaced pivotal supports, two sets of contact springs mounted on said frame, means on said block for operating one or the other set of said contact springs when the block is rocked in one or the other direction, a positioning spring, independent of said contact springs and normally tending to position said block on both pivotal studs, and an operators handle on said block for rocking it on either pivotal support.

7. An operators key for telephone exchanges or the like, comprising frame having two op positely disposed walls and two pairs of oppositely disposed slots in said walls, each pair being widely spaced from the other pair, a shifting block disposed between said walls and having two spaced parallel pivot studs, each stud engaging one pair of opposite wall slots, so that said block is permitted to rock on either or" two spaced pivotal supports, two sets or" contact springs mounted on said frame, means on said block for operating one or the other set of said contact springs when the block is rocked in one or the other direction, a positioning spring, independent of said contact springs and normally tending to position said block on both pivotal studs, said positioning spring being suitably shaped and placed with respect to said pivotal studs to exert a thrust against said block to maintain it in rocked position when it is rocked on one of said studs, but to return the block to normal position when it is rocked on the other stud, and an operators handle on said block for rocking it on either pivotal support.

8. An operators key for telephone exchanges or the like, comprising a frame having two oppositely disposed walls and two pairs of oppositely disposed slots in said walls, each pair being widely spaced from the other pair, the slots in one of said walls being open at corresponding ends, a shifting block disposed between said walls and having two spaced parallel pivot studs, each stud engaging one pair of opposite wall slots, so that said block is permitted to rock on either of two spaced pivotal supports, two sets of contact springs mounted on said frame, means on said block for operating one or the other set of said contact springs when the block is rocked in one or the other direction, and an operators handle on said block for rocking it on either pivotal support.

9. An operators key for telephone exchanges or the like, comprising a frame having two oppositely disposed walls and two pairs of oppositely disposed slots in said walls, each pair being Widely spaced from the other pair, a shifting block disposed between said walls and having two spaced parallel pivot studs, each stud engaging one pair of opposite wall slots, so that said block is per-- mitted to rock on either of two spaced pivotal supports, two sets of contact springs mounted on said frame, means on said block for operating one or the other set of said contact springs when the block is rocked in one or the other direction, a positioning spring, independent of said contact springs and normally tending to position said block on both pivotal supports, a pair of stops for looking said block against simultaneous displacement from both of its pivotal supports and for limiting the rocking motion on either pivotal support and an operators handle for rocking said block on either of its pivotal supports.

MORTEN BALTHAZAR RICHTER. 

